[In vitro evaluation of MR thermometry in the implementation of laser-induced thermotherapy].
OBJECTIVE
To optimize the MR sequences parameter for monitoring hyperthermic effects in the tissue during laser induced thermotherapy (LITT).


METHODS
Experimental studies were performed for the evaluation of MR-thermometry using a contrast-agent-water solution and a pig-liver. A T1-weighted TurboFLASH sequence and a FLASH-2D sequence were used. The TurboFLASH sequence was used with various T1 settings (between 100 and 1250 ms). MR findings were correlated with temperature measurements using a fluoride optical temperature measuring system in a distance of 1, 2, and 5 cm from the laser applicator.


RESULTS
Using the contrast-agent-water solution demonstrated the temperature sensitivity of both sequences. In vitro evaluations using pig liver demonstrated a near linear increase of signal versus increasing tissue temperatures in a distance of 1 cm to the tip of the laser applicator. Optimal visualization of the temperature effects was obtained using a T1 between 100 ms and 400 ms. Using the FLASH-2D sequence a signal loss was documented at a TR of 110 ms.


CONCLUSIONS
MR-thermometry using sequentially TurboFLASH and FLASH-2D sequences allowed a non-invasive monitoring of the laser induced temperature changes.
Vogl
T J
TJ
Strahlenklinik und Poliklinik, Virchow-Klinikum, Humboldt-Universität zu Berlin.
Mack
M G
MG
Hirsch
H H
HH
Müller
P
P
Weinhold
N
N
Wust
P
P
Philipp
C
C
Roggan
A
A
Felix
R
R
D000818:Animals; D001831:Body Temperature; D003287:Contrast Media; D006979:Hyperthermia, Induced; D066298:In Vitro Techniques; D017075:Laser Coagulation; D053685:Laser Therapy; D007834:Lasers; D008099:Liver; D008113:Liver Neoplasms / Q000601:surgery / Q000628:therapy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008991:Monitoring, Physiologic; D013552:Swine; D013821:Thermometers; D013997:Time Factors
D003287:Contrast Media
In-vitro-Evaluierung der MR-Thermometrie zum Einsatz der laserinduzierten Thermotherapie.